US7643900B2ActiveUtilityPatentIndex 27
Method of controlling a screw in a two-stage injection unit and a system for implementing the method
Est. expiryAug 13, 2027(~1.1 yrs left)· nominal 20-yr term from priority
B29C 2945/76187B29C 2945/76933B29C 2945/76076B29C 45/76B29C 2945/76936B29C 2945/76846B29C 2045/547B29C 2945/76605B29C 45/54B29C 2945/76665
27
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0
Cited by
19
References
23
Claims
Abstract
Embodiments of the present invention teach a method of controlling a screw in a two-stage injection unit and a system for implementing the method. For example, a method of controlling a screw in a two-stage injection unit, the method executable at a computing apparatus associated with the two-stage injection unit is disclosed. The method comprises receiving an indication of an operational parameter associated with the screw of the two-stage injection unit; based on the indication of the operational parameter, determining a target speed (S TARGET ) for the screw, the target speed (S TARGET ) being sufficient to enable the screw to produce a required amount of material in a molten state; causing the screw to rotate at the target speed (S TARGET ), thereby causing the screw to operate in a substantially continuous manner.
Claims
exact text as granted — not AI-modified1. A method of controlling a screw in a two-stage injection unit, the method executable at a computing apparatus associated with the two-stage injection unit, the method comprising:
receiving an indication of an operational parameter associated with the screw of the two-stage injection unit;
based on the indication of the operational parameter, determining a target speed (S TARGET ) for the screw, said target speed (S TARGET ) being sufficient to enable the screw to produce a required amount of material in a molten state;
causing the screw to rotate at the target speed (S TARGET ), thereby causing the screw to operate in a substantially continuous manner,
said operational parameter comprising at least: (i) an indication of recovery time (T RECOVERY ); (ii) an indication of idling time (T IDLE ); (iii) an indication of current rotational speed of the screw (S REFERENCE ); and wherein said determining comprises calculating said target speed (S TARGET ) based on a formulae expressed as:
S
TARGET
=
T
RECOVERY
T
RECOVERY
+
T
IDLE
×
S
REFERENCE
.
2. The method of claim 1 , wherein said determining a target speed (S TARGET ) for the screw comprises determining speed (S TARGET ) for the screw such that when the screw rotates at the target speed (S TARGET ), it reaches a back position at an instance in time that substantially coincides with an instant in time when the transfer stage commences.
3. The method of claim 1 , wherein said causing comprises generating a control signal representative of the target speed (S TARGET ).
4. The method of claim 3 , further comprising releasing the control signal towards a screw actuator of the screw.
5. The method of claim 1 , wherein said receiving an indication of an operational parameter comprises:
retrieving a stored operational parameter from an internal memory.
6. The method of claim 5 , wherein said stored operational parameter comprises at least one of:
an indication of linear position of the screw (P SCREW );
an indication of recovery time (T RECOVERY );
an indication of idling time (T IDLE );
an indication of current rotational speed of the screw (S REFERENCE );
an indication of a constant value (V CONSTANT ).
7. The method of claim 5 , further comprising obtaining an indication of stored operational parameter and storing the indication of the stored operational parameter in the internal memory.
8. The method of claim 7 , wherein said obtaining an indication of stored operational parameter comprises receiving the indication of stored operational parameter from at least a first sensor.
9. The method of claim 7 , wherein said obtaining an indication of stored operational parameter comprises appreciating the indication of stored operational parameter by virtue of controlling one or more functions of a molding system incorporating the two-stage injection unit.
10. The method of claim 1 , further comprising executing a verification routine configured to determine if the target speed (S TARGET ) is sufficient to obtain the required amount of material in a molten state.
11. The method of claim 10 , using an operating parameter comprising at least (i) an indication of the target speed (S TARGET ); (ii) an indication of a distance between a current linear position and a back position (D BACK POSITION ); (iii) an indication of a remaining time in a current recovery cycle (T REMAINING ); and (iv) an indication of a constant parameter (V CONSTANT ); wherein said executing a verification routine comprises calculating a current target speed (S TARGET NEW ) based on a formulae expressed as:
S
TARGET
NEW
=
D
BACK
POSITION
×
1
T
REMAINING
×
V
CONSTANT
.
12. The method of claim 11 , further comprising:
if said current target speed (S TARGET NEW ) does not equal to said target speed (S TARGET ) within a variance window, causing the screw to rotate at the current target speed (S TARGET NEW ).
13. The method of claim 12 , wherein said causing the screw to rotate at the current target speed (S TARGET NEW ) comprises generating a control signal representative of the target speed (S TARGET NEW ).
14. The method of claim 13 , further comprising releasing the control signal representative of the target speed (S TARGET NEW ) towards a screw actuator of the screw.
15. The method of claim 10 , wherein said executing a verification routine comprises executing the verification routine at a midpoint of a recovery stage.
16. The method of claim 10 , wherein said executing a verification routine comprises executing the verification routine at a one-third-point of a recovery stage.
17. The method of claim 10 , wherein said executing a verification routine comprises executing the verification routine substantially continuously throughout a recovery stage.
18. The method of claim 1 , wherein said required amount of material comprises an amount equivalent to a desired shot size.
19. A two-stage injection unit comprising:
a barrel with a screw operatively mounted therewithin;
a shooting pot in fluid communication with said barrel;
a computing apparatus operatively coupled to said screw for controlling operation thereof; the computing apparatus being configured:
receive an indication of an operational parameter associated with the screw of the two-stage injection unit;
based on the indication of the operational parameter, determining a target speed (S TARGET ) for the screw;
transmit a control signal representative of the target speed (S TARGET ) towards the screw;
whereby said control signal causes the screw to rotate at the target speed (S TARGET ) in a substantially continuous manner while producing a required amount material in a molten state,
said operational parameter comprising at least: (i) an indication of recovery time (T RECOVERY ); (ii) an indication of idling time (T IDLE ); (iii) an indication of current rotational speed of the screw (S REFERENCE ); and wherein said computing apparatus is configured to calculate said target speed (S TARGET ) based on a formulae expressed as:
S
TARGET
=
T
RECOVERY
T
RECOVERY
+
T
IDLE
×
S
REFERENCE
.
20. The two-stage injection unit of claim 19 , wherein said target speed (S TARGET ) for the screw is determined such that when the screw rotates at the target speed (S TARGET ), it reaches a back position at an instance in time that substantially coincides with an instant in time when the transfer stage commences.
21. The two-stage injection unit of claim 19 , wherein said required amount of material comprises an amount equivalent to a desired shot size.
22. A computer readable storage medium containing a program element for execution by a computing apparatus, the program element for rendering the computing apparatus to:
receive an indication of an operational parameter associated with a screw of a two-stage injection unit;
based on the indication of the operational parameter, determine a target speed (S TARGET ) for the screw, said target speed (S TARGET ) being sufficient to enable the screw to produce a required amount of material in a molten state;
cause the screw to rotate at the target speed (S TARGET ), thereby causing the screw to operate in a substantially continuous manner,
said operational parameter comprising at least: (i) an
indication of recovery time (T RECOVERY ); (ii) an
indication of idling time (T IDLE ); (iii) an indication of current rotational speed of the screw (S REFERENCE );
and wherein said computing apparatus is configured by the program element to calculate said target speed (S TARGET ) based on a formulae expressed as:
S
TARGET
=
T
RECOVERY
T
RECOVERY
+
T
IDLE
×
S
REFERENCE
.
23. The computer readable storage medium of claim 22 , wherein said target speed (S TARGET ) for the screw is determined such that when the screw rotates at the target speed (S TARGET ), it reaches a back position at an instance in time that substantially coincides with an instant in time when the transfer stage commences.Cited by (0)
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